Branch data Line data Source code
1 : : /* crypto/ec/ec_check.c */
2 : : /* ====================================================================
3 : : * Copyright (c) 1998-2002 The OpenSSL Project. All rights reserved.
4 : : *
5 : : * Redistribution and use in source and binary forms, with or without
6 : : * modification, are permitted provided that the following conditions
7 : : * are met:
8 : : *
9 : : * 1. Redistributions of source code must retain the above copyright
10 : : * notice, this list of conditions and the following disclaimer.
11 : : *
12 : : * 2. Redistributions in binary form must reproduce the above copyright
13 : : * notice, this list of conditions and the following disclaimer in
14 : : * the documentation and/or other materials provided with the
15 : : * distribution.
16 : : *
17 : : * 3. All advertising materials mentioning features or use of this
18 : : * software must display the following acknowledgment:
19 : : * "This product includes software developed by the OpenSSL Project
20 : : * for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
21 : : *
22 : : * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
23 : : * endorse or promote products derived from this software without
24 : : * prior written permission. For written permission, please contact
25 : : * openssl-core@openssl.org.
26 : : *
27 : : * 5. Products derived from this software may not be called "OpenSSL"
28 : : * nor may "OpenSSL" appear in their names without prior written
29 : : * permission of the OpenSSL Project.
30 : : *
31 : : * 6. Redistributions of any form whatsoever must retain the following
32 : : * acknowledgment:
33 : : * "This product includes software developed by the OpenSSL Project
34 : : * for use in the OpenSSL Toolkit (http://www.openssl.org/)"
35 : : *
36 : : * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
37 : : * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
38 : : * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
39 : : * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
40 : : * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
41 : : * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
42 : : * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
43 : : * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
44 : : * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
45 : : * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
46 : : * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
47 : : * OF THE POSSIBILITY OF SUCH DAMAGE.
48 : : * ====================================================================
49 : : *
50 : : * This product includes cryptographic software written by Eric Young
51 : : * (eay@cryptsoft.com). This product includes software written by Tim
52 : : * Hudson (tjh@cryptsoft.com).
53 : : *
54 : : */
55 : :
56 : : #include "ec_lcl.h"
57 : : #include <openssl/err.h>
58 : :
59 : 81 : int EC_GROUP_check(const EC_GROUP *group, BN_CTX *ctx)
60 : : {
61 : 81 : int ret = 0;
62 : : BIGNUM *order;
63 : 81 : BN_CTX *new_ctx = NULL;
64 : 81 : EC_POINT *point = NULL;
65 : :
66 [ + - ]: 81 : if (ctx == NULL)
67 : : {
68 : 81 : ctx = new_ctx = BN_CTX_new();
69 [ - + ]: 81 : if (ctx == NULL)
70 : : {
71 : 0 : ECerr(EC_F_EC_GROUP_CHECK, ERR_R_MALLOC_FAILURE);
72 : 0 : goto err;
73 : : }
74 : : }
75 : 81 : BN_CTX_start(ctx);
76 [ + - ]: 81 : if ((order = BN_CTX_get(ctx)) == NULL) goto err;
77 : :
78 : : /* check the discriminant */
79 [ - + ]: 81 : if (!EC_GROUP_check_discriminant(group, ctx))
80 : : {
81 : 0 : ECerr(EC_F_EC_GROUP_CHECK, EC_R_DISCRIMINANT_IS_ZERO);
82 : 0 : goto err;
83 : : }
84 : :
85 : : /* check the generator */
86 [ - + ]: 81 : if (group->generator == NULL)
87 : : {
88 : 0 : ECerr(EC_F_EC_GROUP_CHECK, EC_R_UNDEFINED_GENERATOR);
89 : 0 : goto err;
90 : : }
91 [ - + ]: 81 : if (!EC_POINT_is_on_curve(group, group->generator, ctx))
92 : : {
93 : 0 : ECerr(EC_F_EC_GROUP_CHECK, EC_R_POINT_IS_NOT_ON_CURVE);
94 : 0 : goto err;
95 : : }
96 : :
97 : : /* check the order of the generator */
98 [ + - ]: 81 : if ((point = EC_POINT_new(group)) == NULL) goto err;
99 [ + - ]: 81 : if (!EC_GROUP_get_order(group, order, ctx)) goto err;
100 [ - + ]: 81 : if (BN_is_zero(order))
101 : : {
102 : 0 : ECerr(EC_F_EC_GROUP_CHECK, EC_R_UNDEFINED_ORDER);
103 : 0 : goto err;
104 : : }
105 : :
106 [ + - ]: 81 : if (!EC_POINT_mul(group, point, order, NULL, NULL, ctx)) goto err;
107 [ - + ]: 81 : if (!EC_POINT_is_at_infinity(group, point))
108 : : {
109 : 0 : ECerr(EC_F_EC_GROUP_CHECK, EC_R_INVALID_GROUP_ORDER);
110 : 0 : goto err;
111 : : }
112 : :
113 : : ret = 1;
114 : :
115 : : err:
116 [ + - ]: 81 : if (ctx != NULL)
117 : 81 : BN_CTX_end(ctx);
118 [ + - ]: 81 : if (new_ctx != NULL)
119 : 81 : BN_CTX_free(new_ctx);
120 [ + - ]: 81 : if (point)
121 : 81 : EC_POINT_free(point);
122 : 81 : return ret;
123 : : }
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